WRACKLINE

About

Made in a harbour office, above the tide gauge.

Wrackline started in 2019 as a spreadsheet for our own sailing club at Ossett Head. It now runs on the phones of sailors, anglers, surfers and walkers along the whole coast.

Boats lying on the mud of a walled harbour at low tide
building tide software on this coast
7 years
building tide software on this coast
two developers, one hydrographer, one on the duty phone
4 people
two developers, one hydrographer, one on the duty phone
longest wait for a reply from support
1 day
longest wait for a reply from support

Why another tide app?

The club’s printed tide table was right about the moon and silent about everything else. After a winter when three boats touched the bar on "safe" tides, we started logging the harbour gauge against the table and publishing the difference on the noticeboard.

People read the difference more than the table. That became the idea: a prediction that tells you how good it is, port by port, and warns you on the days the weather will push it off.

The app still does one thing. It tells you where the water will be. It does not sell your location, it does not show adverts, and the person who answers the duty phone has sailed the bar you are asking about.

A rocky shore at low tide seen from a green cliff top, with the town beyond
A stone slipway running down to wide sand flats at low tide

Three rules we build by

Say what it cannot do

Every port page publishes its error. When the weather will matter, the app says so on the day.

Nothing leaves the phone

No account, no location tracking, no advertising IDs. The business is the subscription, not you.

Answer the phone

The duty phone is answered from six in the morning until ten at night, by someone who knows the tide.